1. Field of the Invention
The present disclosure relates generally to the field of firearms. More specifically, the present invention relates to a lower receiver for a firearm and an associated collapsible buttstock.
2. Description of Related Art
The AR-15 is based on the AR-10, which was designed by Eugene Stoner, Robert Fremont, and L. James Sullivan of the Fairchild ArmaLite Corporation in 1957. Today, there are numerous variants of the AR-15 that are manufactured by a number of companies. The AR-15 and its various related derivative platforms are used by civilians, law enforcement personnel, and military forces around the world.
Various firearms, such as, for example, the AR-15 or M-4 style firearms utilize a variable position buttstock 2 that is slidable and lockable at various positions along a buffer tube 5. A typical variable position buttstock 2 can be locked into a collapsed position, as illustrated in FIG. 1, or locked into a fully extended position, as illustrated in FIG. 2.
As further illustrated in FIGS. 3 and 4, the typical buffer tube 2 includes a capped cylindrical portion having a threaded portion 8 for installation into a firearm receiver. Typically, an endplate 6 and a lock ring 4 are utilized to complete installation of the buffer tube on the receiver. A key protrusion 7 extends from the cylindrical portion 9, typically at the 6 o'clock position. An interior portion of the key protrusion includes a plurality of spaced apart recesses or apertures that interact with a retractable bolt to lock the buttstock 2 in a desired position relative to the buffer tube 5.
Certain retrofit collapsible stock assemblies are available. These assemblies require use of a shortened, proprietary buffer tube and use of a proprietary bolt carrier, which includes a built-in buffer. In order to install these retrofit collapsible stock assemblies, the upper receiver must be attached to the lower receiver and the existing buffer tube and buffer retainer must be removed from the lower receiver. Next, the proprietary bolt carrier must be inserted through the buffer tube attachment aperture. Then, the proprietary bolt carrier, a proprietary buffer spring, and a proprietary stock adapter are appropriately positioned at the rear of the receiver. Once appropriately positioned, the proprietary buffer tube is then affixed to the lower receiver, via the buffer tube attachment aperture, to secure the components to the receiver.
Finally, the stock is attached to the stock adapter.
Any discussion of documents, acts, materials, devices, articles, or the like, which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.